1. Field of the Invention
The present invention relates generally to a motor control system for controlling operation of a plurality of motors, and more particularly to such a motor control system arranged to reduce production cost and necessary space therefor as compared with conventional ones.
2. Description of the Prior Art
For example, an automatic air-conditioning system of automotive vehicles is provided with four motors for accomplishing control of opening degree of a door for mixing warm and cool air, change-over action of air blow-out openings, opening-and-closing action of a water valve and the like, in which sequential control of the four motors is made in response to signals from a sensor and the like by using a motor control system. Such a motor control system usually includes a microcomputer and a plurality of integrated circuits each connected to each motor. The integrated circuit is adapted to control the operation of each motor in response to signal output from the microcomputer.
However, such a motor control system necessitates one motor driving integrated circuit for each motor, and therefore the number of the integrated circuits increases as the number of the motors increases. Additionally, the microcomputer is required to have its output ports of the number of two times of the number of the motors. This increases production cost of the motor control system while increasing space occupied by the motor control system.